PBGA singulated substrate for model melamine cleaning

ABSTRACT

A new method is provided to clean melamine deposits from tools and components that are used to form molds around and to therewith encapsulate BGA devices. The cleaning process applies a dummy BGA substrate as part of and during the cleaning procedure. This dummy BGA substrate replaces the conventionally used copper strips that shield areas of the molding tools during the cleaning cycle. The dummy copper strips require, during and as part of the melamine cleaning process, frequent cleaning, which adds considerable to the time and expense of the melamine cleaning process.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The invention relates to the fabrication of integrated circuit devices,and more particularly, to a method of cleaning PBGA packages thatresults in reduced-cost cleaning procedures while maximizing thefrequency of cleaning cycles.

(2) Description of the Prior Art

The continuing decrease in semiconductor device dimensions coupled withthe continuing increase in device densities have, over the years, led tothe development of a number of packaging techniques for the packaging ofvery dense and complex semiconductor devices. Increased devicecomplexity further required improved methods of accessing thesemiconductor devices by means of the device input/output (I/O)connections. To accommodate an increased number of I/O connections,semiconductor packages have evolved from lead frame packages such as theDual In Line (DIL) and Quad Flat Package (QFP) to laminated packagessuch as the Ball Grid Array (BGA) package.

Concurrent with the use of various packaging techniques, methods andprocesses have been developed that are aimed at providing increasedprotection to the packaged semiconductor devices. Where semiconductordevices are mounted on a supporting substrate, such as a Printed CircuitBoard (PCB), these devices are typically encapsulated prior to theirmounting on the PCB so as to minimize physical damage to the devices andthe fragile interconnecting wires or circuitry that are used tointerconnect the semiconductor devices. Not only does the encapsulationprevent physical damage to the packaged device, the encapsulation alsoisolates the packaged device from the environment and in this mannerprevents corrosive effects on device components and wiring that canresult from contact with moisture or from surface oxidation.

The packaging arrangements that are typically used for the packaging ofsemiconductor devices employ a number of different approaches, wherebythese approaches can be distinguished between methods of providing a(rigid or flexible) support structure on which the semiconductor deviceis mounted with interconnect lines provided on the surface of thesupport structure, methods of providing a chip-on-surface mountingtechnique whereby the supporting structure can comprise laminated layersof interconnect lines that are used in combination with interconnectlines on the surface of the supporting structure and methods ofproviding laminated packages that use cavities for the mounting of thesemiconductor devices. Where possible, the methods of packaging aredesigned such that automated packaging processes can be used for obviousreasons of costs incurred as part of the packaging process. In thisrespect, the supporting structure that uses a cavity for the mounting ofthe semiconductor device does not lend itself to automatic packagingprocesses since, for the various packaging approaches that have beenhighlighted, the semiconductor device must, after it has been packaged,as yet be encapsulated, which is a processing step that cannot readilybe monitored using cavity based supporting structures.

For the process of encapsulating the semiconductor device, transfermolds are typically used whereby the transfer mold is, during theprocess of encapsulation, positioned over the to be encapsulated deviceand removed from that location after the encapsulation has beencompleted. Using this process, the encapsulant covers at least thesemiconductor device and any surrounding (wire bonded) interconnect wirebut may, in addition, cover larger surface portions of the supportingstructure.

For a typical mounting of a chip on the surface of a laminatedsubstrate, whereby the substrate can be either ceramic (making thesubstrate rigid) or can contain an organic or plastic material (makingthe substrate flexible), electrical interconnect lines are formed withinthe laminated layers of the substrate using conventional methods ofmetal deposition and patterning that apply standard photolithographicmethods and procedures. The various layer of the laminated substrate areinsulated from each other using dielectric materials such as a polyimidethat can be used to separate for instance metal power and ground planesin the substrate. Electrical connections between the layers of thelaminated substrate are formed by conductive vias, the opening of thevia is, after this opening has been formed, filled with a conductivematerial in order to establish the electrically conductive path betweenthe various layers. After the required interconnect patterns have inthis manner been established in the laminated substrate, thesemiconductor chip is positioned on the surface of the substrate andattached to the substrate by a suitable die attach material such asepoxy. This layer of epoxy serves not only to hold the semiconductor diein place but also serves as a heat transfer medium between the die andthe substrate. The top surface of the semiconductor die is connected(wire bonded) to the conductive traces on the surface of the substrateafter which the die including the bonded wires can be encapsulate.Electrical interconnects must then be established between the substrate(to which the die is at this time connected) and the surroundingelectrical circuits to which the substrate is connected. Electricaltraces have also been provided in the lower surface of the substrate, asolder mask is deposited over the bottom surface of the substrate,contact balls are positioned in alignment with the contact points in thelower surface of the substrate and re-flowed thereby connecting thecontact balls with the electrical traces in the bottom surface of thesubstrate and completing the interconnects between the (surface mounted)semiconductor die and the contact balls of the supporting substrate. Themethod described above is a method of connecting a semiconductor deviceusing wire bond techniques. In addition and as a substitute to thewire-bonding techniques, known connection techniques in the art such asflip-chip techniques can be applied to interconnect the semiconductordie.

The above indicated method of packaging a semiconductor die employs one(lower) mold, the process of applying the mold compound typically usesan upper mold that matches with and overlays the lower mold. Suitablerecesses are formed in this case in both the lower and the upper mold inorder to enable and facilitate the process of applying the mold aroundthe semiconductor device. During the process of applying the moldcompound over the semiconductor die, the die that at this time has beenmounted on the surface of a substrate, is inserted with its substrateinto a cavity that has been provided for this purpose in a lower mold.An upper mold is aligned with the lower mold, a recess has for purposesof alignment (between the two molds) been provided in the upper moldwhile a matching opening is provided in the lower mold. An alignment pinis inserted through the opening in the lower mold after which thealignment opening in the upper mold is aligned with the alignment pinthat protrudes through the lower mold.

The upper mold contains a cavity that has the internal contours of themold that needs to be applied over the semiconductor die. After theupper mold has been aligned with the lower mold, the mold cavity in theupper mold overlays the semiconductor die that has been inserted in thelower mold and that is mounted on a laminated substrate. The moldmaterial is then inserted, typically using the same opening that is usedto insert the inter-mold alignment pin, from where the mold is forcedvia a channel (that is provided between the upper and the lower mold)into the mold cavity of the upper mold.

Manufacturing automation and the control of the cost that is incurredduring the molding (encapsulation) process requires that the process ofmolding of the devices can proceed applying the mold to a number ofdevices in a relatively rapid sequence whereby a number of devices areprocessed simultaneously. This leads to the processing of multiplesubstrates simultaneously, the multiple substrates are provided andhandled in strip form. The multiple substrates are interconnected andform a substrate strip, after the molding process has been completed thesubstrates are separated or singulated from each other. This process isfurther described below.

It must further be realized that, concurrent with substrate strips,multiple molds are typically contained within one mold bar during theprocess of inserting the mold compound. These mold bars are individuallyremovable, the mold bars can be differentiated between upper and lowermold bars. The upper and lower mold bars are further mounted in andsupported by an upper and a lower mold frame and can be readily removedfrom the mold frames such that flexibility and easy convertibility fromone type of mold to the other is provided. The source of the mold thatis inserted over the semiconductor die is referred to as the mold pot,it is common practice to provide a multiplicity of mold pots on aseparate bar (the runner bar) that is mounted between two adjacent moldbars and that serves to supply the mold compound to the individual moldsfor simultaneous molding.

FIG. 1 shows a top view of a substrate strip 10 that contains fourindividual substrates 12. Openings 14 have been provided in thesubstrate strip 10, these openings are used for attachment of thesubstrate strip 10 to other processing equipment during additionalprocessing steps, these processing steps are not further described atthis time. Stress relieve between the individual substrates 12 and thesubstrate strip 10 is provided by the substrate separation slots 16.These separation slots assure that the substrates 12, although thesubstrate 12 are interconnected to and are part of the substrate strip10, act as individual units and do not incur warp or any other stressrelated deformity during the handling of the substrate strip 10 or atthe time that the substrates 12 are singulated. Each of the corners ofthe substrates 12 is further provided with an opening 18, which improvesthe singulation results by providing a well controlled circumference ofthe singulated substrate. The semiconductor die or chip is placed in themiddle of each of the substrates 12, these die placement areas arehighlighted as areas 20.

The substrates 12 that are shown in FIG. 1 are the laminated substratesthat have previously been described and contain layers of interconnectlines and points of electrical interconnect on both surfaces of thesubstrate. These interconnect points are, for reasons of clarity, notshown in FIG. 1. The laminated substrate 12 shown in FIG. 1 are thesubstrates that are further used for the creation of BGA packages andpackage interconnects. The substrates 12 are, in other words, desiredend products of a processing sequence, these substrates 12 are onlyindirectly related to the invention.

U.S. Pat. No. 5,886,398 (Low et al.) shows a process that involves atransfer molding and substrate and singulation. The molded packages havean internal mold gate. However, this reference differs from theinvention.

U.S. Pat. No. 5,780,933 (Ohmori) shows a package using a transfermolding. However, this reference differs from the invention.

U.S. Pat. No. 5,795,799 (Hosoya) shows a molding process with transfermolding.

U.S. Pat. No. 5,939,778 (Boutin et al.) shows a related molding process.

SUMMARY OF THE INVENTION

A principle objective of the invention is to provide an improved methodof cleaning of mold material that is typically used to encapsulate BGAdevices.

In accordance with the objectives of the invention a new method isprovided to clean melamine deposits from tools and components that areused to form molds around and to therewith encapsulate BGA devices. Thecleaning process applies a dummy BGA substrate as part of and during thecleaning procedure. This dummy BGA substrate replaces the conventionallyused copper strips that shield areas of the molding tools during thecleaning cycle. The dummy copper strips require, during and as part ofthe melamine cleaning process, frequent cleaning, which addsconsiderable to the time and expense of the melamine cleaning process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top view of a conventional substrate strip.

FIG. 2 shows a top view of two cavity bars that are separated by arunner bar, this during the operation of forming BGA device molding.

FIG. 3 shows the processing flow of the invention that is required toachieve BGA singulated substrate mold melamine cleaning. The processingof the invention addresses only and exclusively the cleaning cycle thatis required to clean a mold chase and to thereby remove and remainingmelamine from a production mold case.

FIG. 4 shows a three dimensional view of a BGA magazine into whichsingulated substrates have been inserted.

FIG. 5 shows a top view of a substrate strip after singulation. This isthe dummy or singulated substrate strip from which the laminatedsubstrates 12 (FIG. 1) and the thereupon mounted chips have beenremoved. This dummy substrate is used during the cleaning process of theinvention.

FIG. 6 shows a vertical cross section of the two cavity bars that areseparated by a runner bar (see FIG. 2), containing singulated BGAstrips, at the time that the top mold chase and the bottom mold chaseare closed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For conventional methods of cleaning melamine from the surface of runnerbars and cavity bars, specially designed dummy strips (made of copper)are used that shield or protect certain areas against penetration ofmelamine into these areas. The objective of the shielding is to assurethat no melamine penetrates these areas (during the process of cleaningremnants of melamine from the chase) so that, as a consequence, nomelamine needs to as yet be removed therefrom. These dummy strips,typically made of copper, must, for a typical cleaning cycle, be cleaneda number of times during and as part of the cleaning cycle. Thiscleaning of the dummy strips can require between 24 and 36 cleaningcycles of the dummy strips before the required end result of removingmelamine has been obtained. This repetitive cleaning of these speciallycreated dummy strips of copper is very time consuming and expensive andmust therefore, if possible, be avoided.

The process of the invention provides a method where the conventional,specially provided dummy strips of copper are not used as part of themelamine cleaning process. In its place the process of the inventionuses a dummy singulated substrate strip that does not (as opposed to theconventional copper strips) need to be cleaned during and as part of themelamine cleaning process and that, at the end of the melamine cleaningprocess, can be discarded without incurring any significant cost to thecleaning process. During regular melamine insertion, after thisinsertion has been completed, the devices are, mounted on theirindividual substrates, removed from the substrate strip. The substratestrip, after the removal of the devices from the strip, now becomes adummy substrate strip. These dummy substrate strips are in aconventional cleaning process, not used. The process of the inventionmakes use of the dummy substrate strips and substitutes, during theprocess of cleaning of the melamine insertion chase, the dummy stripsfor the convention (copper) specially designed strip. Since the dummystrips of the invention are normally discarded, the process of theinvention reduces the cleaning cost by negating the need to clean theconvention (copper) strips and replacing these strips with dummy stripsthat can be discarded without incurring any cost.

FIG. 2 shows a top view of the molding equipment to which two substratestrips 10 and 10′ have been attached. The two cavity bars 22 and 22′ areseparated by the runner bar or center block 24, all three bars arecontained within and supported by the mold chase 26. Substrate strip 10is attached to cavity bar 22 via the openings 14, these openings 14align with corresponding pins that protrude from the surface of thecavity bar 22. Openings 13 are the areas where the substrates arelocated prior to singulation. Each of the openings 13 is contained withthe substrate strip 10 and 10′ and is aligned with a cavity 28/28′,which are the cavities that has been created in the cavity bars 22/22′.Each of the cavities 28/28′ is connected with the mold supply containers(pots) 30 by means of a channel 32 that is part of the runner bar 24. Itis clear that the mold that is supplied from the mold container 30 flowsthrough channel 32 and enters the mold cavity 28/28′ via the channelopening 34/34′.

One of the problems that is encountered in applying the mold material asdetailed above is that the mold compound enters the mold cavity via thechannel 32 and the channel opening 34/34′ after which time must beallotted for the mold to solidify. Since there is no clear divisionbetween the path of the flow of the mold that clearly separates theregions where the mold is to harden (the mold cavities 28/28′) and thepath through which the mold is supplied to the mold cavity (the moldchannels 32 and the channel openings 34/34′), it is to be expected thatthe mold will not only settle and harden in the mold cavity 28 but willalso settle and harden in the mold channels 32 and the channel openings34/34′. The undesired mold must be removed in order to retain only themold within the mold cavity 28/28′, a process-of removal that must beperformed prior to the singulation of the substrate strips 10/10′ intoindividual substrates. The fact that the channel openings 34/34′ are ofa smaller diameter than the diameter of the channels 32 makes thisprocess of removal somewhat easier since these narrow openings 34/34′provide some separation between the mold cavities 28/28′ and the moldchannels 32. It might be suggested that the process of removal of theexcess mold material can be accomplished by removing the runner bar 24from in-between the substrates 10 and 10′. It must however be rememberedthat the mold partially flows over the surface of the substrate on itsway to the mold cavity. This mold has the tendency to adhere to thesurface of the substrate after the mold has been allowed to solidify. Intherefore removing the runner bar 24 from between the two substrates 10and 10′, the mold that adheres to the surface of the substrate 10 and10′ tends to damage this surface at this time of runner bar 24 removal.This process of surface damage is further aggravated if the moldcompound is allowed to accumulate between successive mold operations. Toprevent this accumulation, it is common practice to remove remainingmold compound from the surface of the runner bar 24 and specificallyfrom the mold channels 32 and the mold channel openings 34/34′ betweenmold operations.

One of the materials that is used as a mold compound is melamine, thecleaning of the melamine is performed at regular intervals and after acertain number of mold operations have been performed. Current practicecalls for one cleaning operation after 200 operations of mold insertion.

In the current practice as shown in FIG. 2, the strips 10 and 10′ arecopper or brass strips. It is the purpose of the invention to usesingulated BGA substrates that have a geometric pattern that is similarto the geometric pattern of substrate strips 10 and 10′. Thesesingulated BGA substrate will replace the currently used copper stripsduring the melamine insertion process.

Referring now specifically to FIG. 3, there is shown the processing flowof the invention that is aimed at applying a mold compound over thesurface of BGA devices and removing melamine from the surface ofcomponents such as cavity bars and runner bars, after the mold compoundhas been applied over the surface of BGA devices.

The first step of the process of the invention, FIG. 3, step 40, is theselection of a BGA substrate strip, which is any BGA substrate stripfrom which the BGA devices have been singulated. This BGA substrate isfurther detailed as BGA substrate 11 in FIG. 5. This selected BGAsubstrate is for the subsequent mold insertion and cleaning proceduredesignated as the dummy BGA substrate strip.

After the dummy BGA substrate strip has been obtained as indicated aboveunder FIG. 3, step 40, this dummy substrate is categorized andidentified in accordance with the substrate thickness and the substratesize, such as a size of 27×27 mm or 35×35 mm and a thickness of 0.36 mmor 0.56 mm. This categorization, FIG. 3, step 42, serves as the basisfor using the dummy substrate strip during the cleaning cycle, whereby aparticular dummy substrate strip is matched with and used for BGAdevices that have characteristics of thickness and size that areidentical to the characteristics of thickness and size as the dummy BGAsubstrate strip.

FIG. 3, step 44 shows that the singulated dummy substrate strip is nextloaded onto a BGA magazine. The BGA magazine is further highlighted inFIG. 4 following. After the singulated dummy substrate strips have beenloaded onto the BGA magazine, the magazine is moved to the productionwhere the cleaning process takes place. The BGA magazine is a standardcarrier used for the storing and moving of BGA substrate strips. Assuch, the BGA magazine that is shown in FIG. 4 is not basic to theprocess of the invention but is used since its use is standard practicein a BGA molding insertion environment. This use of the BGA magazine isfurther facilitated since the dummy singulated substrate strips have thesame physical characteristics as the production strips that have beenprocessed using the molding chase that is to be cleaned using the dummysingulated substrate strips.

FIG. 3, step 46 indicates that, after the singulated dummy substratestrips have been loaded onto the BGA magazine and the BGA magazine hasbeen moved to the mold insertion station that needs to be cleaned, adummy singulated BGA substrate strip is removed from the BGA magazineand placed on the mold chase 26 (FIG. 2). After two dummy singulatedsubstrate strips have been loaded into the mold chase 26, the mold chaseis closed, FIG. 3, step 48, and a melamine compound (functioning as acleaning agent) is inserted (flows through) the pots 30, the runners 32and the cavities 28 of mold chase 28 (FIG. 2), FIG. 3, step 50. Themelamine is used as a cleaning compound because it forms one solid withthe melamine that needs to be cleaned from inside surfaces of the moldchase so that, when removing the melamine that is runs into the moldchase, the surfaces that contain melamine remnants are also cleaned ofthe melamine. At the completion of this step (time or volume of insertedmold compound driven) the mold chase is opened, FIG. 3, step 52.

The mold chase at this time in the mold cleaning cycle of the mold chasecontains a body of melamine mold compound that can now be removed fromthe mold chase, and, with it, the dummy singulated substrate strip canbe removed. The dummy substrate strip has served the same function asthe previously used (copper) strips that were used for partial chaseshielding and protection, the discarding of the dummy substrate strip atthis time does not, as previously pointed out, add or incur any expenseto the mold cleaning cycle of the mold chase.

FIG. 4 shows a three-dimensional view of a BGA magazine 50 into whichsingulated substrates 11 have been inserted. A label 52 is attached tothe surface of magazine 50 for easy identification of the magazine 50.It is clear that the magazine 50 provides a method of simultaneouslystoring and handling multiple singulated substrates 11.

FIG. 5 shows a top view of a dummy substrate strip 11 after singulation.The substrate strip 13 has four openings 13 from where the individualsubstrate and their chips have been removed or singulated. The itemsthat are highlighted in FIG. 5 are identical to these items as they havebeen highlighted for FIG. 1 above and need therefore not be furtherexplained at this time.

FIG. 6 shows a vertical cross section of the two cavity bars that areseparated by a runner bar of FIG. 2 containing singulated BGA strips,this at the time that the top mold chase 26′ (not shown in FIG. 2) andthe bottom mold chase 26 (see also FIG. 2) are brought into closephysical proximity to each other (are “closed”). As previouslyhighlighted in FIG. 2, 22 and 22′ are the cavity bars 22 and 22′ thatare separated by the runner bar or center block 24. The upper mold chaseis highlighted with 26′, the lower mold chase (see also FIG. 2) ishighlighted with 26. Singulated BGA strips 11 are inserted in the cavitybars 22 and 22′, the mold cavity (see also FIG. 2) is shown andhighlighted with 28. springs 27 press the singulated EGA strip againstthe upper mold chase 26′.

The process of the invention has therefore achieved the following:

a simplification of the cleaning operation by removing the previouslyrequired steps of cleaning dummy copper strips; this latter process isvery time consuming in view of the fact that the process must berepeated numerous times during one melamine cleaning operation, and

the process of the invention has replaced the use of dummy copper stripswith the use of a dummy BGA substrate strips which perform the samefunction as the previously used dummy copper strips but which can bereadily discarded at the completion of the melamine cleaning cyclewithout thereby adding significant to the cost of the melamine cleaningoperation.

Although the invention has been described and illustrated with referenceto specific illustrative embodiments thereof, it is not intended thatthe invention be limited to those illustrative embodiments. Thoseskilled in the art will recognize that variations and modifications canbe made without departing from the spirit of the invention. It istherefore intended to include within the invention all such variationsand modifications which fall within the scope of the appended claims andequivalents thereof.

What is claimed is:
 1. A method of removing mold compound from tools and components that are used to encapsulate semiconductor devices, comprising the steps of: providing a mold chase having an upper and a lower mold chase; providing dummy singulated semiconductor device substrate strips; placing said dummy singulated semiconductor device substrate strips onto said lower mold chase said lower mold chase having been provided with mold pots, mold runners and mold cavities whereby said dummy singulated semiconductor device substrate strips have openings that align with said mold cavities; closing said mold chase by lowering said upper mold chase over said lower mold chase thereby enclosing said dummy singulated semiconductor device substrate strips between said upper and lower mold chase; flowing a cleaning compound through said mold pots, said mold runners and said mold cavities; opening said mold chase by raising said upper mold chase from said lower mold chase thereby exposing said dummy singulated semiconductor device substrate strips between said upper and lower mold chase further exposing said cleaning compound; and removing and discarding said cleaning compound, removing and discarding said dummy singulated semiconductor device substrate strips from said mold chase.
 2. The method of claim 1 wherein said dummy singulated semiconductor device substrate strips are production semiconductor device substrate strips from which all therein comprised semiconductor devices and their substrates have been removed, creating openings in said dummy singulated semiconductor device substrate strips that align with said mold pots in said lower mold chase.
 3. The method of claim 1 wherein said cleaning compound comprises melamine.
 4. The method of claim 1 wherein said semiconductor devices are Plastic Ball Grid Array devices.
 5. The method of claim 1 wherein said mold compounds comprise melamine compound.
 6. The method of claim 1 further comprising additional step of categorizing said dummy singulated semiconductor device substrate strips by observing physical characteristics of size and thickness of said dummy singulated semiconductor device substrate strips, whereby each selected dummy singulated semiconductor device substrate strip is assigned an operational code or designation an operational code or designation reflects future processes of said mold compound cleaning for which a categorized dummy singulated semiconductor device substrate strip can be used, said additional step to be performed prior to said step of placing said dummy singulated semiconductor device substrate strips onto said lower mold chase.
 7. The method of claim 6 wherein said physical characteristics of size and thickness comprise substrate sizes 27×27 mm or 35×35 mm or any other suitable substrate size, and substrate thicknesses of 0.36 mm or 0.56 mm or any other suitable substrate thickness.
 8. The method of claim 6 wherein said dummy singulated semiconductor device substrate strips, after the step of categorizing said dummy singulated semiconductor device substrate strips has been completed, are assigned to and used for cleaning mold compound from surfaces that have been used during a molding process of semiconductor devices that have characteristics of size and thickness that are equal to said characteristics of size and thickness of said dummy singulated semiconductor device substrate strips.
 9. A method of removing mold compounds from a mold chase that is used to encapsulate semiconductor devices, said mold chase to comprise an upper and a lower mold chase, said lower mold chase to comprise mold pots mold runners and mold cavities, the said method comprising: selecting one or more semiconductor device substrate strips from among a collection of production semiconductor device substrate strips said selected semiconductor device substrate strips to be used as dummy semiconductor device substrate strips during the process of the invention; removing all semiconductor devices and thereto connected substrates from said selected semiconductor device substrate strips thereby creating dummy singulated semiconductor device substrate strips; categorizing said dummy singulated semiconductor device substrate strips by observing dimensional characteristics of size and thickness of said dummy singulated semiconductor device substrate strips thereby classifying said dummy singulated semiconductor device substrate strips for use during a process of removing said mold compound from said mold chase that is used to encapsulate semiconductor devices; loading said categorized dummy singulated semiconductor device substrate strips into a semiconductor device magazine; moving said semiconductor device magazine to said mold chase that is used to encapsulate semiconductor devices; selecting one or more of said categorized dummy singulated semiconductor device substrate strips; inserting said one or more selected categorized dummy singulated semiconductor device substrate strips into said lower mold chase; enclosing said one or more of said selected categorized dummy singulated semiconductor device substrate strips between said upper and said lower mold chase by lowering said upper mold chase over said lower mold chase; flowing a cleaning agent through said mold pots, mold runners, and mold cavities of said lower mold chase; allowing for a measurable time while said cleaning agent react with said mold compound that is to be cleaned from said mold chase; exposing said one or more of said selected categorized dummy singulated semiconductor device substrate strips by lifting said upper mold chase away from said lower mold chase; and removing and discarding said categorized dummy singulated semiconductor device substrate strips together with said cleaning agent from said mold chase.
 10. The method of claim 9 wherein said semiconductor devices are Plastic Ball Grid Array devices.
 11. The method of claim 9 wherein said mold compounds comprises melamine compound.
 12. The method of claim 9 wherein said cleaning agent comprises melamine compound.
 13. The method of claim 9 wherein said categorizing said dummy singulated semiconductor device substrate strips consist of observing physical characteristics of size and thickness of said dummy singulated semiconductor device substrate strips whereby each selected dummy singulated semiconductor device substrate strip is assigned an operational code or designation such that this code or designation reflects future processes of melamine cleaning for which a categorized dummy singulated semiconductor device substrate strip can be used.
 14. The method of claim 13 wherein said physical characteristics of size and thickness comprise substrate sizes 27×27 mm or 35×35 mm or any other suitable substrate size and substrate thicknesses of 0.36 mm or 0.56 mm or any other suitable substrate thickness.
 15. The method of claim 9 wherein said dummy singulated semiconductor device substrate strips, after the step of categorizing said dummy singulated semiconductor device substrate strips has been completed, are assigned to and used for cleaning of mold compound from surfaces that have been used during a molding process of semiconductor devices that have characteristics of size and thickness that are equal to said characteristics of size and thickness of said dummy singulated semiconductor device substrate strips.
 16. The method of claim 9 whereby loading of said categorized dummy singulated semiconductor device substrate strips into a semiconductor device magazine is performed such that orientation of said dummy substrate in said semiconductor device magazine does not deviate from production unit orientation. 